Continuous casting of an ingot is commonly performed by injecting metal melted by vacuum arc melting or electron beam melting into a bottomless mold and withdrawing the metal downward while being solidified.
Patent Document 1 discloses an automatic control method for plasma melting casting, in which titanium or a titanium alloy is subjected to plasma arc melting in an argon gas atmosphere and injected into a mold for solidification. Performing the plasma arc melting in an inert gas atmosphere, unlike the electron beam melting in vacuum, allows casting of not only pure titanium, but also a titanium alloy.